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Biophysical
Terms modified by Biophysical Selected AbstractsInfluence of environmental stress on skin tone, color and melanogenesis in Japanese skinINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005K. Kikuchi Introduction It is needless to say that one of the most potent environmental stress for melanogenesis of the human skin is the effect of ultraviolet (UV) light from the sunlight. Characteristic skin aging as a result of this UV light is recognized as photoaging. Clinical features in photoaging are wrinkles, skin laxity, coarseness, leathery, yellowing, lentigenes, mottled pigmentation, telangiectasia, sebaceous hypertrophy and purpura. There is an apparent difference in clinical features in photoaging among different races, i.e. between Caucasians, African American and Asians that include Japanese. Not only photo skin type but also environmental factors, such as climate, latitude, altitude and their habit of sunbathing, smoking and skin care influence the characteristic development of their photoaging. Racial difference in photoaging Caucasians tend to develop skin laxity and fine wrinkles more than Asians [1]. Asians tend to produce coarser wrinkles than the Caucasians although their development is rather late in life. There is also a difference in the skin color. Pigmentation is an earliest and prominent skin changes in Asians [1] and it increases with age [2]. In contrast, pigmentation is not apparent in the Caucasians although redness probably because of an increase in cutaneous vascularization becomes prominent in middle aged Caucasians [2]. Chung reported that seborrheic keratosis is a major pigmentary lesion in men, whereas hyperpigmented macules are prominent features in women in Koreans [3]. Melanogenesis pigmentation disorders in Japanese Ephelides (freckles) are commonly found in those with photo skin type I who have fair skin and red eyes and blond hair. They are also found in the Japanese. Clinical feature reveals that multiple small pigmentary macules on sun-exposed areas mainly on the mid-portion of the face. These lesions seem to be familial, becoming apparent even in early childhood after sun exposure. Melasma is an acquired pigmentary disorder commonly found in middle aged Japanese women characterized by irregular brown macules and patches on the sun-exposed areas on the face typically as bilaterally present macules on the cheeks. An increase in sex hormones as a result of pregnancy and intake of contraceptive pills is one of the etiological factors to develop melasma. Sun exposure also worsens it. Nevus of Ota is also a common pigmentary disorder found in the Japanese. It is usually unilateral, blue-brown to slate-gray pigmentary macules on the eyelid and cheek that appear in early childhood or in puberty. Acquired dermal melanocytosis is also a pigmentary disorder, in which dermal melanocytes are found as shown in nevus of Ota, characterized by bilateral brown to blue-gray macules on the forehead, temple, eyelid and malar areas in middle aged Japanese women. This tends to be misdiagnosed as melasma. Solar lentigo is an acquired pigmented macule induced by sun exposure. Solar lentigines are usually multiple, circumscribed brown macules. There are two types of solar lentigo. One is a small macular type, characterized by multiple, small brown macules whose diameter is less than 5 mm, being similar to ephelides (freckles). The other type is a large macular type, characterized by a few round to oval, brown macules whose diameter is beyond 1 cm. Some of their surface are hyperkeratotic and become elevated to produce seborrheic keratosis. Again, the early sign of photoaging in Japanese is pigmentated spots and these pigmentation disorders increase with age. Among the pigmentary changes, nevus of Ota, acquired dermal melanocytosis, melasma and large macular type of solar lentigo are characteristic skin changes found in the Japanese in addition to ephelides and small macular type of solar lentigo. Seasonal changes of the various functional properties of the skin including skin color assessed by non-invasive bioengineering techniques [4]. When we consider skin tone, color and melanogenesis, UV light from the sunlight is the most potent environmental stress, although we cannot forget also the important influence of environmental relative humidity affects our skin functions as well as its appearance. We investigated seasonal influences on the various properties of the skin in 39 healthy Japanese females consisting of different age groups. Their skin is thought to be affected by the UV light in summer, and by the exposure to the dry and cold air in winter. Materials and methods Biophysical, non-invasive measurements, including transepidermal water loss (TEWL) as a parameter for the barrier function of the stratum corneum (SC), high frequency conductance as a parameter for the hydration state of the SC, skin color and casual surface lipid levels, were conducted during late summer and winter months. Skin color was determined with a chromameter according to the L*a*b* CIE 1976 system, where L* is an attribute on the luminance scale, a* that on the red versus green scale and b* that on the yellow versus blue scale. All the measurements were conducted in an environment controlled-chamber (21 ± 1 °C room temperature, and 50 ± 3% relative humidity). Results The barrier function of the SC was found to be significantly impaired in winter on the cheek as compared with that measured in summer, whereas no such seasonal change was apparent both in the hydration state of the SC and sebum levels on the cheek. In the assessment of the skin color on the cheek, a significant increase in a* (redness) and a decrease in b* (yellowness) were observed in winter. In contrast, on the flexor forearm, the values of L* (luminescence) increased in winter, but no seasonal change was noted in the values of a* and b*. In this study, skin changes with aging were also found by the non-invasive bioengineering methods. The value of TEWL on the cheek tended to increase with age, whereas no significant change was observed in the value of TEWL on the forearm. In the assessment of skin color, b* value on the cheek significantly increased with age whereas a* and L* values on the cheek did not show any significant change with age. Summary of this study We think that such an increase in yellowness with aging of the cheek skin is a phenomenon unique to the Japanese (Asians) since an increase in b* value was not observed in Caucasians [2]. The facial skin that is always exposed shows barrier impairment in a dry and cold winter environment and demonstrates increased yellowness in skin color because of a prolonged exposure to the UV light from the sun in the summer season. The non-invasive bioengineering methods are useful to demonstrate even invisible seasonal changes occurring in the same individuals and changes with age occurring in the skin. References 1.,Goh, S.H. The treatment of visible signs of senescence: the Asian experience. Br. J. Dermatol.122, 105,109 (1990). 2.,LeFur, I., Numagami, K., Guinot, C. et al. Age-related reference values of skin color in Caucasian and Japanese healthy women according to skin site. Pigment Cell Res. 7, 67 (1999). 3.,Chung, J.H., Lee, S.H., Youn, C.S. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 4.,Kikuchi, K., Kobayashi, H., Le Fur, I. et al. Winter season affects more severely the facial skin than the forearm skin: comparative biophysical studies conducted in the same Japanese females in later summer and winter. Exog. Dermatol. 1, 32,38 (2002). [source] Voltage-Gated Sodium Channels: Therapeutic Targets for PainPAIN MEDICINE, Issue 7 2009Sulayman D. Dib-Hajj PhD ABSTRACT Objective., To provide an overview of the role of voltage-gated sodium channels in pathophysiology of acquired and inherited pain states, and of recent developments that validate these channels as therapeutic targets for treating chronic pain. Background., Neuropathic and inflammatory pain conditions are major medical needs worldwide with only partial or low efficacy treatment options currently available. An important role of voltage-gated sodium channels in many different pain states has been established in animal models and, empirically, in humans, where sodium channel blockers partially ameliorate pain. Animal studies have causally linked changes in sodium channel expression and modulation that alter channel gating properties or current density in nociceptor neurons to different pain states. Biophysical and pharmacological studies have identified the sodium channel isoforms Nav1.3, Nav1.7, Nav1.8, and Nav1.9 as particularly important in the pathophysiology of different pain syndromes. Recently, gain-of-function mutations in SCN9A, the gene which encodes Nav1.7, have been linked to two human-inherited pain syndromes, inherited erythromelalgia and paroxysmal extreme pain disorder, while loss-of-function mutations in SCN9A have been linked to complete insensitivity to pain. Studies on firing properties of sensory neurons of dorsal root ganglia demonstrate that the effects of gain-of-function mutations in Nav1.7 on the excitability of these neurons depend on the presence of Nav1.8, which suggests a similar physiological interaction of these two channels in humans carrying the Nav1.7 pain mutation. Conclusions., These studies suggest that isoform-specific blockers of these channels or targeting of their modulators may provide novel approaches to treatment of pain. [source] Biophysical and human influences on plant species richness in grasslands: Comparing variegated landscapes in subtropical and temperate regionsAUSTRAL ECOLOGY, Issue 3 2001S. Mcintyre Abstract A survey of grassy woodlands in the Queensland subtropics was conducted, recording herbaceous species richness at 212 sites on three properties (2756 ha). A range of habitats typical of cattle grazing enterprises was sampled and site variables included lithology, slope position, tree density, soil disturbance, soil enrichment and grazing. Results were compared with a previously published survey of temperate grasslands. Lithology, slope position and tree density had relatively minor effects on plant species richness, although in both surveys there was some evidence of lower species richness on the more fertile substrates. Soil disturbance and soil enrichment significantly reduced the richness of native species in both surveys, while exotic species were insensitive (subtropics) or increased (temperate) with disturbance. Rare native species were highly sensitive to disturbances, including grazing, in the temperate study. Although some trends were similar for rare species in the subtropics, the results were not significant and there were complex interactions between grazing, lithology and slope position. Grazing did not have a negative effect on native species richness, except in the closely grazed patches within pastures, and then only on the most intensively developed property. At the scale recorded (30 m2), the native pastures, roadsides and stock routes sampled in the subtropics appear to be among the most species-rich grasslands ever reported, both nationally and globally. Native species richness was approximately 50% higher than the temperate survey figures across all the comparable habitats. While there are no clear reasons for this result, potential explanations are proposed. [source] The Northwest Forest Plan as a Model for Broad-Scale Ecosystem Management: a Social PerspectiveCONSERVATION BIOLOGY, Issue 2 2006SUSAN CHARNLEY conservación y desarrollo; comunidades rurales; gestión forestal; monitoreo socioeconómico Abstract:,I evaluated the Northwest Forest Plan as a model for ecosystem management to achieve social and economic goals in communities located around federal forests in the U.S. Pacific Northwest. My assessment is based on the results of socioeconomic monitoring conducted to evaluate progress in achieving the plan's goals during its first 10 years. The assessment criteria I used related to economic development and social justice. The Northwest Forest Plan incorporated economic development and social justice goals in its design. Socioeconomic monitoring results indicate that plan implementation to achieve those goals met with mixed success, however. I hypothesize there are two important reasons the plan's socioeconomic goals were not fully met: some of the key assumptions underlying the implementation strategies were flawed and agency institutional capacity to achieve the goals was limited. To improve broad-scale ecosystem management in the future, decision makers should ensure that natural-resource management policies are socially acceptable; land-management agencies have the institutional capacity to achieve their management goals; and social and economic management goals (and the strategies for implementing them) are based on accurate assumptions about the relations between the resources being managed and well-being in local communities. One of the difficulties of incorporating economic development and social justice goals in conservation initiatives is finding ways to link conservation behavior and development activities. From a social perspective, the Northwest Forest Plan as a model for ecosystem management is perhaps most valuable in its attempt to link the biophysical and socioeconomic goals of forest management by creating high-quality jobs for residents of forest communities in forest stewardship and ecosystem management work, thereby contributing to conservation. Resumen:,Evalué el Plan Forestal del Noroeste como un modelo para la gestión de ecosistemas para alcanzar metas sociales y económicas en comunidades localizadas alrededor de bosques federales en el Pacífico Noroeste de E.U.A. Mi evaluación se basa en los resultados del monitoreo socioeconómico desarrollado para evaluar el progreso en el logro de las metas del plan durantes sus 10 primeros años. Los criterios de evaluación que utilicé se relacionan con el desarrollo económico y la justicia social. El diseño del Plan Forestal del Noroeste incorporó metas de desarrollo económico y de justicia social. Sin embargo, los resultados del monitoreo socioeconómico indican que éxito en la implementación del plan para alcanzar esas metas fue combinado. Postulé la hipótesis de que hay dos razones importantes por las que las metas socioeconómicas del plan no se cumplieron totalmente: algunas de las suposiciones clave en las estrategias de implementación fueron deficientes y la capacidad institucional de la agencia para alcanzar las metas era limitada. Para mejorar la gestión de ecosistemas a gran escala en el futuro, los tomadores de decisiones deberán asegurarse que las políticas de gestión de recursos naturales sean aceptables socialmente; que las agencias de gestión de tierras tengan la capacidad institucional para cumplir sus metas de gestión; y que las metas de gestión sociales y económicas (y las estrategias para su implementación) se basen en suposiciones precisas de las relaciones entre los recursos a gestionar y el bienestar de las comunidades locales. La manera de vincular comportamiento de conservación y actividades de desarrollo es una de las dificultades para la incorporación de metas de desarrollo económico y de justicia social en las iniciativas de conservación. Desde una perspectiva social, el Plan Forestal del Noroeste como modelo para la gestión de ecosistemas quizás es más valioso por su intento de vincular las metas biofísicas y socioeconómicas de la gestión forestal mediante la creación de empleos de alta calidad para residentes de las comunidades en labores de regulación y supervisión forestal y de gestión de ecosistemas, por lo tanto contribuye a la conservación. [source] A model for range expansion of an introduced species: the common waxbill Estrilda astrild in PortugalDIVERSITY AND DISTRIBUTIONS, Issue 6 2002Tiago Silva Abstract. The common waxbill Estrilda astrild was first introduced to Portugal from Africa in 1964, and has spread across much of the country and into Spain. We modelled the expansion of the common waxbill on a 20 × 20 km UTM grid in 4-year periods from 1964 to 1999. The time variation of the square root of the occupied area shows that this expansion process is stabilizing in Portugal, and reasons for this are discussed. Several methods used to model biological expansions are not appropriate for the present case, because little quantitative data are available on the species ecology and because this expansion has been spatially heterogeneous. Instead, colonization on a grid was modelled as a function of several biophysical and spatio-temporal variables through the fitting of a multivariate autologistic equation. This approach allows examination of the underlying factors affecting the colonization process. In the case of the common waxbill it was associated positively with its occurrence in adjacent cells, and affected negatively by altitude and higher levels of solar radiation. [source] LAND RICH AND DATA POOR: MODELLING REQUIREMENTS IN AUSTRALIA'S FAR NORTHECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 3 2005Natalie Stoeckl Economic models have long been used as a way of organising and presenting information for policy makers interested in large regions,e.g. nations,and recent advances in information technology make the goal of developing models for decision makers in other locales a realistic one. The research on which this paper focuses was part of large project investigating the feasibility and desirability of developing a multi-disciplinary computer model of the Australian Savannas. In the large project, researchers were broken in to three teams: those considering the biophysical, demographic, and economic aspects of the modelling problem. This paper presents findings from part of the economic component of the investigation: that which sought information from key local ,stakeholders' about the type of information that would be useful to them. Responses indicate that many of Australia's existing economic models are capable of providing the ,right' type of information; but at too coarse a geographic scale for those in remote regions. Evidently, there is a need for developing other models. [source] A New Chrna4 Mutation with Low Penetrance in Nocturnal Frontal Lobe EpilepsyEPILEPSIA, Issue 7 2003Tobias Leniger Summary: Purpose: To identify and characterize the mutation(s) causing nocturnal frontal lobe epilepsy in a German extended family. Methods: Neuronal nicotinic acetylcholine receptor (nAChR) subunit genes were screened by direct sequencing. Once a CHRNA4 mutation was identified, its biophysical and pharmacologic properties were characterized by expression experiments in Xenopus oocytes. Results: We report a new CHRNA4 mutation, causing a ,4-T265I amino acid exchange at the extracellular end of the second transmembrane domain (TM). Functional studies of ,4-T265I revealed an increased ACh sensitivity of the mutated receptors. ,4-T265I is associated with an unusual low penetrance of the epilepsy phenotype. Sequencing of the TM1-TM3 parts of the 1 known nAChR subunits did not support a two-locus model involving a second nAChR sequence variation. Conclusions: nAChR mutations found in familial epilepsy are not always associated with an autosomal dominant mode of inheritance. ,4-T265I is the first nAChR allele showing a markedly reduced penetrance consistent with a major gene effect. The low penetrance of the mutation is probably caused by unknown genetic or environmental factors or both. [source] Specific cleavage of the DNase-I binding loop dramatically decreases the thermal stability of actinFEBS JOURNAL, Issue 18 2010Anastasia V. Pivovarova Differential scanning calorimetry was used to investigate the thermal unfolding of actin specifically cleaved within the DNaseI-binding loop between residues Met47-Gly48 or Gly42-Val43 by two bacterial proteases, subtilisin or ECP32/grimelysin (ECP), respectively. The results obtained show that both cleavages strongly decreased the thermal stability of monomeric actin with either ATP or ADP as a bound nucleotide. An even more pronounced difference in the thermal stability between the cleaved and intact actin was observed when both actins were polymerized into filaments. Similar to intact F-actin, both cleaved F-actins were significantly stabilized by phalloidin and aluminum fluoride; however, in all cases, the thermal stability of the cleaved F-actins was much lower than that of intact F-actin, and the stability of ECP-cleaved F-actin was lower than that of subtilisin-cleaved F-actin. These results confirm that the DNaseI-binding loop is involved in the stabilization of the actin structure, both in monomers and in the filament subunits, and suggest that the thermal stability of actin depends, at least partially, on the conformation of the nucleotide-binding cleft. Moreover, an additional destabilization of the unstable cleaved actin upon ATP/ADP replacement provides experimental evidence for the highly dynamic actin structure that cannot be simply open or closed, but rather should be considered as being able to adopt multiple conformations. Structured digital abstract ,,MINT-7980274: Actin (uniprotkb:P68135) and Actin (uniprotkb:P68135) bind (MI:0407) by biophysical (MI:0013) [source] Dynamic interactions of proteins in complex networks: a more structured viewFEBS JOURNAL, Issue 19 2009Amelie Stein Virtually every process in a cell is carried out by macromolecular complexes whose actions need to be perfectly orchestrated. The synchronization and regulation of these biological functions is indeed critical and is usually carried out by complex networks of transient protein interactions. Here, we review some of the many strategies that proteins in regulatory networks use to achieve the dynamic plasticity necessary to rapidly respond to diverse cellular needs. More specifically, we present recent work on the molecular bases of transient peptide-mediated interactions and the role that post-translational modifications and disordered regions might play. Finally, in light of some recent findings, we speculate on the possibility of a new regulatory code for intrinsically disordered proteins and the potential biophysical and functional advantages that disorder might provide. [source] An integrated biogeochemical and economic analysis of bioenergy crops in the Midwestern United StatesGCB BIOENERGY, Issue 5 2010ATUL K. JAIN Abstract This study integrates a biophysical model with a county-specific economic analysis of breakeven prices of bioenergy crop production to assess the biophysical and economic potential of biofuel production in the Midwestern United States. The bioenergy crops considered in this study include a genotype of Miscanthus, Miscanthus×giganteus, and the Cave-in-Rock breed of switchgrass (Panicum virgatum). The estimated average peak biomass yield for miscanthus in the Midwestern states ranges between 7 and 48 metric tons dry matter per hectare per year ( t DM ha,1 yr,1), while that for switchgrass is between 10 and 16 t DM ha,1 yr,1. With the exception of Minnesota and Wisconsin, where miscanthus yields are likely to be low due to cold soil temperatures, the yield of miscanthus is on average more than two times higher than yield of switchgrass. We find that the breakeven price, which includes the cost of producing the crop and the opportunity cost of land, of producing miscanthus ranges from $53 t,1 DM in Missouri to $153 t,1 DM in Minnesota in the low-cost scenario. Corresponding costs for switchgrass are $88 t,1 DM in Missouri to $144 t,1 DM in Minnesota. In the high-cost scenario, the lowest cost for miscanthus is $85 t,1 DM and for switchgrass is $118 t,1 DM, both in Missouri. These two scenarios differ in their assumptions about ease of establishing the perennial crops, nutrient requirements and harvesting costs and losses. The differences in the breakeven prices across states and across crops are mainly driven by bioenergy and row crop yields per hectare. Our results suggest that while high yields per unit of land of bioenergy crops are critical for the competitiveness of bioenergy feedstocks, the yields of the row crops they seek to displace are also an important consideration. Even high yielding crops, such as miscanthus, are likely to be economically attractive only in some locations in the Midwest given the high yields of corn and soybean in the region. [source] Justice in River Management: Community Perceptions from the Hunter Valley, New South Wales, AustraliaGEOGRAPHICAL RESEARCH, Issue 2 2005Mick Hillman Abstract Dealing with differing and sometimes conflicting criteria for priority-setting is an essential part of sustainable natural resource management. However, all too often, these ethical and political considerations are neglected within a planning regime based upon apparently ,objective' biophysical assessment techniques. Input into associated decision-making processes is also frequently restricted to a narrow range of ,stakes' based upon historical and geographic circumstances. This paper reports on the findings of interviews and discussion groups in the Hunter Valley, New South Wales, which aimed to canvass the diversity of perceptions of distributive and procedural justice in river rehabilitation. A range of biophysical and social criteria for setting priorities in rehabilitation work was identified. Participants also had differing ideas on the composition of decision-making bodies and on decision-making processes. The key implications of these findings are that sustainable river management policy needs to openly address differing conceptions of justice and that rehabilitation practice should be holistic, transdisciplinary and concerned with both outcome and process. [source] Ecohydrological feedbacks and linkages associated with land degradation: a case study from MexicoHYDROLOGICAL PROCESSES, Issue 15 2006Elisabeth Huber-Sannwald Abstract Land degradation and desertification are major environmental problems of human societies in drylands of North and South America. Mexico is one of the most severely affected countries. An assessment of how both biophysical and socio-economic processes simultaneously affect, and are affected by, land degradation is recognized as one of the most important and challenging topics in the research on global change. Towards meeting this challenge, in June 2004 an interdisciplinary mix of scientists assembled in Mexico to participate in a workshop convened by the ARIDnet network. The focus of the workshop was to apply a new conceptual framework,the Dahlem Desertification Paradigm (DDP),to La Amapola, a small rural community located in the Central Plateau of Mexico. The DDP aims to advance understanding of global desertification issues by focusing on the interrelationships within coupled human-environment systems that cause desertification. In this paper we summarize the conclusions of the La Amapola workshop. First, we present a brief review of some of the broader issues and concerns of global desertification, which led to the formation of ARIDnet and to the DDP. Second, we provide an overview of land degradation issues in La Amapola, highlighting examples of hydrological linkages between biophysical and socio-economic factors. Third, we summarize our findings in a conceptual model, which highlights linkages between biophysical and socio-economic factors in La Amapola, and the role of hydrology in desertification. Lastly, we discuss the results derived from the application of the major assertions of the DDP to La Amapola. The numerous feedbacks, linkages, and causal pathways between the biophysical and human dimensions suggest that hydrology is the fundamental component of the livelihoods of rural communities in this region of Mexico, and thus it is of central importance when evaluating desertification. Copyright © 2006 John Wiley & Sons, Ltd. [source] Ethnic skin types: are there differences in skin structure and function?,INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2006A. V. Rawlings Synopsis People of skin of colour comprise the majority of the world's population and Asian subjects comprise more than half of the total population of the earth. Even so, the literature on the characteristics of the subjects with skin of colour is limited. Several groups over the past decades have attempted to decipher the underlying differences in skin structure and function in different ethnic skin types. However, most of these studies have been of small scale and in some studies interindividual differences in skin quality overwhelm any racial differences. There has been a recent call for more studies to address genetic together with phenotypic differences among different racial groups and in this respect several large-scale studies have been conducted recently. The most obvious ethnic skin difference relates to skin colour which is dominated by the presence of melanin. The photoprotection derived from this polymer influences the rate of the skin aging changes between the different racial groups. However, all racial groups are eventually subjected to the photoaging process. Generally Caucasians have an earlier onset and greater skin wrinkling and sagging signs than other skin types and in general increased pigmentary problems are seen in skin of colour although one large study reported that East Asians living in the U.S.A. had the least pigment spots. Induction of a hyperpigmentary response is thought to be through signaling by the protease-activated receptor-2 which together with its activating protease is increased in the epidermis of subjects with skin of colour. Changes in skin biophysical properties with age demonstrate that the more darkly pigmented subjects retaining younger skin properties compared with the more lightly pigmented groups. However, despite having a more compact stratum corneum (SC) there are conflicting reports on barrier function in these subjects. Nevertheless, upon a chemical or mechanical challenge the SC barrier function is reported to be stronger in subjects with darker skin despite having the reported lowest ceramide levels. One has to remember that barrier function relates to the total architecture of the SC and not just its lipid levels. Asian skin is reported to possess a similar basal transepidermal water loss (TEWL) to Caucasian skin and similar ceramide levels but upon mechanical challenge it has the weakest barrier function. Differences in intercellular cohesion are obviously apparent. In contrast reduced SC natural moisturizing factor levels have been reported compared with Caucasian and African American skin. These differences will contribute to differences in desquamation but few data are available. One recent study has shown reduced epidermal Cathepsin L2 levels in darker skin types which if also occurs in the SC could contribute to the known skin ashing problems these subjects experience. In very general terms as the desquamatory enzymes are extruded with the lamellar granules subjects with lowered SC lipid levels are expected to have lowered desquamatory enzyme levels. Increased pores size, sebum secretion and skin surface microflora occur in Negroid subjects. Equally increased mast cell granule size occurs in these subjects. The frequency of skin sensitivity is quite similar across different racial groups but the stimuli for its induction shows subtle differences. Nevertheless, several studies indicate that Asian skin maybe more sensitive to exogenous chemicals probably due to a thinner SC and higher eccrine gland density. In conclusion, we know more of the biophysical and somatosensory characteristics of ethnic skin types but clearly, there is still more to learn and especially about the inherent underlying biological differences in ethnic skin types. Résumé, Les gens qui ont une peau de couleur représentent la majorité de la population mondiale et les sujets asiatiques en représentent plus de la moitié. Pourtant la littérature consacrée aux caractéristiques de ces sujets est limitée. Plusieurs groupes de travail ont essayé au cours des dernières années de comprendre les différences sous-jacentes de la structure et de la fonction de la peau de différentes ethnies. Maisla plupart de ces études ont été réalisées à petite échelle et dans certains cas les différences observées entre les individus au niveau de la qualité de la peau ne font pas ressortir de différence entre races. Récemment, un besoin d'études reliant les diffèrences génétiques et phénotypiques entre différents groupes raciaux s'est fait sentir et de ce fait beaucoup d'études à grande èchelle ont été entreprises. La différence la plus évidente, entre les peaux ethniques, est leur couleur liée à la présence de la mélanine. La photoprotection induite par ce polymère influence le taux de vieillissement de la peau entre les différents groupes raciaux qui finalement sont tous sujets au processus de photovieillissement. Généralement, les caucasiens ont des signes plus précoces et plus importants de formation de rides et de relâchement de la peau; en général, les problèmes d'augmentation de la pigmentation sont observés sur les peaux de couleur, bien qu'une grande étude ait rapporté que des sujets originaires de l'Asie de l'Est vivant aux U.S.A. avaient le moins de taches pigmentaires. On pense que la réponse d'une induction hyperpigmentaire est due à un signal envoyé par le récepteur 2 activé par une protéase. Le récepteur 2 augmente en même temps que la protéase activatrice dans l'épiderme des sujets ayant une peau de couleur. Les changements dans les propriètés biophysiques de la peau en fonction de l'âge montrent que les sujets qui ont la pigmentation la plus sombre gardent une peau plus jeune par comparaison aux groupes qui possèdent une pigmentation moins forte. Toutefois, bien qu'ayant un stratum corneum plus compact, il existe des rapports divergents sur la fonction barrière de ces sujets. Dans le cas d'agression chimique ou mécanique, la fonction barrière du stratum corneum est considérée plus forte chez les sujets à peau plus foncée, malgré leurs taux plus faibles encéramide. On doit garder à l'esprit que la fonction barrière du stratum corneum dépend de toute son architecture et pas seulement de sa teneur en lipides. On considère que la peau asiatique à unePIE (TEWL) basale similaire à la peau caucasienne, ainsi que des taux en céramides comparables, mais on constate que dans le cas d'agression mécanique, elle possède un effet barrière le plus faible. Des différences dans la cohésion intercellulaire sont évidentes. A contrario, on a mis en évidence des taux d'hydratation (NMF) plus faibles dans son stratum corneum, comparativement à la peau caucasienne et afro-américaine. Ces différences expliquent les variations au niveau de la desquamation, mais on a très peu de données sur ce sujet. Une étude récente a mis en évidence des taux réduits de Cathepsin L2 dans l'épiderme des types de peau plus sombre, ce qui, si cela se produisait dans le stratum corneum, expliquerait les problèmes biens connus de cendrage de la peau que ces sujets connaissent. En terme très gènéral, étant donné que les enzymes liées à la desquamation sont libérées avec les granules lamellaires, on s'attend à ce que les sujets ayant des taux de lipides faibles dans le stratum corneum aient des taux d'enzymes liés à la desquamation faibles. On constate chez les sujets noirs une augmentation de la taille des pores, de la sécrétion du sébum et de la microflore cutanée. On observe également chez ces sujets une augmentation de la taille des granules mastocellulaires. Le phénomène de peau sensible se retrouve à une fréquence similaire dans les différents groupes raciaux, mais il existe des différences subtiles dans lesstimuli nécessaires pour l'induire. En tout cas, plusieurs études montrent que la peau asiatique est peut-être plus sensible aux produits chimiques exogènes, ce qui probablement est dûà un stratum corneum plus mince et à une densité de glandes eccrines plus élevées. En conclusion, c'est sur les caractéristiques biophysiques et somato-sensorielles des différents types de peaux ethniques que nous en savons plus, mais il est clair qu'il nous reste à comprendre encore beaucoup de choses principalement sur leurs différences biologiques. [source] Global classification of human facial healthy skin using PLS discriminant analysis and clustering analysisINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2001C Guinot Synopsis Today's classifications of healthy skin are predominantly based on a very limited number of skin characteristics, such as skin oiliness or susceptibility to sun exposure. The aim of the present analysis was to set up a global classification of healthy facial skin, using mathematical models. This classification is based on clinical, biophysical skin characteristics and self-reported information related to the skin, as well as the results of a theoretical skin classification assessed separately for the frontal and the malar zones of the face. In order to maximize the predictive power of the models with a minimum of variables, the Partial Least Square (PLS) discriminant analysis method was used. The resulting PLS components were subjected to clustering analyses to identify the plausible number of clusters and to group the individuals according to their proximities. Using this approach, four PLS components could be constructed and six clusters were found relevant. So, from the 36 hypothetical combinations of the theoretical skin types classification, we tended to a strengthened six classes proposal. Our data suggest that the association of the PLS discriminant analysis and the clustering methods leads to a valid and simple way to classify healthy human skin and represents a potentially useful tool for cosmetic and dermatological research. Résumé Les classifications actuelles qui définissent une peau saine sont fondées principalement sur un nombre très limité de caractéristiques cutanées telles que l'aspect gras de la peau ou sa sensibilité au soleil. Cette analyse a pour but d'établir une classification globale de la peau humaine saine du visage à l'aide de modèles mathématiques. Une recherche de typologie a été effectuée à partir des caractéristiques cliniques et biophysiques de la peau du visage des individus tout en tenant compte d'une classification théorique, reflet de l'expertise des dermatologues, appréciée sur les zones frontale et malaire du visage. Pour accroître l'efficacité prédictive des modèles avec un minimum de variables, la méthode d'analyse discriminante PLS (Partial Least Square) a été utilisée. Des méthodes de classification ont été appliquées aux composantes PLS obtenues afin de déterminer le nombre le plus vraisemblable de classes et pour regrouper les sujets selon leurs proximités. Grâce à cette approche, quatre composantes PLS ont pu être construites et six classes se sont avérées pertinentes. Ce travail a abouti à une proposition de classification à six classes plus vraisemblable et acceptable que les 36 combinaisons possibles de la classification théorique proposée. Nos données suggèrent que l'association de l'analyse discriminante PLS aux méthodes de classification permet d'obtenir de façon simple et appropriée une classification de la peau humaine saine et représente un outil potentiel utile dans le domaine de la recherche en cosmétologie et en dermatologie. [source] Use of vibrational spectroscopy to study protein and DNA structure, hydration, and binding of biomolecules: A combined theoretical and experimental approachINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 5 2006K. J. Jalkanen Abstract We report on our work with vibrational absorption, vibrational circular dichroism, Raman scattering, Raman optical activity, and surface-enhanced Raman spectroscopy to study protein and DNA structure, hydration, and the binding of ligands, drugs, pesticides, or herbicides via a combined theoretical and experimental approach. The systems we have studied systematically are the amino acids (L -alanine, L -tryptophan, and L -histidine), peptides (N -4271 acetyl L -alanine N,-methyl amide, N -acetyl L -tryptophan N,-methyl amide, N -acetyl L -histidine N,-methyl amide, L -alanyl L -alanine, tri- L -serine, N -acetyl L -alanine L -proline L -tyrosine N,-methyl amide, Leu-enkephalin, cyclo-(gly- L -pro)3, N -acetyl (L -alanine)nN,-methyl amide), 3-methyl indole, and a variety of small molecules (dichlobenil and 2,6-dochlorobenzamide) of relevance to the protein systems under study. We have used molecular mechanics, the SCC-DFTB, SCC-DFTB+disp, RHF, MP2, and DFT methodologies for the modeling studies with the goal of interpreting the experimentally measured vibrational spectra for these molecules to the greatest extent possible and to use this combined approach to understand the structure, function, and electronic properties of these molecules in their various environments. The application of these spectroscopies to biophysical and environmental assays is expanding, and therefore a thorough understanding of the phenomenon from a rigorous theoretical basis is required. In addition, we give some exciting and new preliminary results which allow us to extend our methods to even larger and more complex systems. The work presented here is the current state of the art to this ever and fast changing field of theoretical spectroscopic interpretation and use of VA, VCD, Raman, ROA, EA, and ECD spectroscopies. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] The effects of osmotic stress on the structure and function of the cell nucleusJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2010John D. Finan Abstract Osmotic stress is a potent regulator of the normal function of cells that are exposed to osmotically active environments under physiologic or pathologic conditions. The ability of cells to alter gene expression and metabolic activity in response to changes in the osmotic environment provides an additional regulatory mechanism for a diverse array of tissues and organs in the human body. In addition to the activation of various osmotically- or volume-activated ion channels, osmotic stress may also act on the genome via a direct biophysical pathway. Changes in extracellular osmolality alter cell volume, and therefore, the concentration of intracellular macromolecules. In turn, intracellular macromolecule concentration is a key physical parameter affecting the spatial organization and pressurization of the nucleus. Hyper-osmotic stress shrinks the nucleus and causes it to assume a convoluted shape, whereas hypo-osmotic stress swells the nucleus to a size that is limited by stretch of the nuclear lamina and induces a smooth, round shape of the nucleus. These behaviors are consistent with a model of the nucleus as a charged core/shell structure pressurized by uneven partition of macromolecules between the nucleoplasm and the cytoplasm. These osmotically-induced alterations in the internal structure and arrangement of chromatin, as well as potential changes in the nuclear membrane and pores are hypothesized to influence gene transcription and/or nucleocytoplasmic transport. A further understanding of the biophysical and biochemical mechanisms involved in these processes would have important ramifications for a range of fields including differentiation, migration, mechanotransduction, DNA repair, and tumorigenesis. J. Cell. Biochem. 109: 460,467, 2010. © 2009 Wiley-Liss, Inc. [source] Fusion core structure of the severe acute respiratory syndrome coronavirus (SARS-CoV): In search of potent SARS-CoV entry inhibitorsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2008Ling-Hon Matthew Chu Abstract Severe acute respiratory coronavirus (SARS-CoV) spike (S) glycoprotein fusion core consists of a six-helix bundle with the three C-terminal heptad repeat (HR2) helices packed against a central coiled-coil of the other three N-terminal heptad repeat (HR1) helices. Each of the three peripheral HR2 helices shows prominent contacts with the hydrophobic surface of the central HR1 coiled-coil. The concerted protein,protein interactions among the HR helices are responsible for the fusion event that leads to the release of the SARS-CoV nucleocapsid into the target host-cell. In this investigation, we applied recombinant protein and synthetic peptide-based biophysical assays to characterize the biological activities of the HR helices. In a parallel experiment, we employed a HIV-luc/SARS pseudotyped virus entry inhibition assay to screen for potent inhibitory activities on HR peptides derived from the SARS-CoV S protein HR regions and a series of other small-molecule drugs. Three HR peptides and five small-molecule drugs were identified as potential inhibitors. ADS-J1, which has been used to interfere with the fusogenesis of HIV-1 onto CD4+ cells, demonstrated the highest HIV-luc/SARS pseudotyped virus-entry inhibition activity among the other small-molecule drugs. Molecular modeling analysis suggested that ADS-J1 may bind to the deep pocket of the hydrophobic groove on the surface of the central coiled-coil of SARS-CoV S HR protein and prevent the entrance of the SARS-CoV into the host cells. J. Cell. Biochem. 104: 2335,2347, 2008. © 2008 Wiley-Liss, Inc. [source] Correlates of smoking among adolescents with asthmaJOURNAL OF CLINICAL NURSING, Issue 5-6 2010Su-Er Guo Aims and objective., This study examined the correlates of smoking among asthmatic adolescents to gain a better understanding of who is at particular risk. Background., Smoking is especially harmful to individuals with asthma. However, smoking is surprisingly prevalent among asthmatic individuals, with prevalence rates similar to or higher than those of the general adult or adolescent populations. Despite this notable finding, there has been little research about factors (i.e. biophysical, psychosocial and behavioural) influencing asthmatic adolescents' tobacco use patterns. Design., A Canadian provincial cross-sectional survey. Method., The study about adolescents' tobacco use and health status was conducted in secondary schools in 2004, 608 asthmatic adolescents participated. Demographic factors, biophysical (body mass index and physical health), psychosocial factors (parents' and peers' smoking, environmental tobacco smoke exposure and depression) and behavioural factors (marijuana use, alcohol use and exercise frequency) were explored. Multinomial logistic regression analyses were conducted to identify risk factors associated with tobacco use. Results and conclusions., Of the 608 asthmatic adolescents, 17·4% currently smoked and 12·0% formerly smoked. Girls, compared with boys, were more likely to smoke (OR: 3·34, 95% CI: 1·62,6·96) after adjusting for differences in the other demographic, biophysical, psychosocial and behavioural factors. Asthmatic girls who had relatively higher body mass index, were in the higher school grades, used marijuana or alcohol, had minor to severe depressive symptoms, had environmental tobacco smoke exposure in their homes and had friends who smoked or were currently more likely to smoke. The former smokers had similar risk factors including higher body mass index, environmental tobacco smoke exposure at home, friends who smoked and marijuana use. Relevance to clinical practice., Despite their health condition, asthmatic adolescents continue currently or formerly to smoke. Gender appropriate prevention and cessation interventions for asthmatic adolescents may need to address important psychosocial and environmental factors that increase the risk of these adolescents initiating and maintaining tobacco use. [source] Impact of eucalyptus and pine growing on rural livelihood: the lesson from Bukoba area, north western TanzaniaAFRICAN JOURNAL OF ECOLOGY, Issue 2009Phillip K. MwanukuziArticle first published online: 3 FEB 200 Abstract Sustainable resource management intends to allocate resources in such a way that unnecessary deterioration of biophysical and socio-economical systems is avoided. In Bukoba Area where rainfalls are plenty, evergreen grasslands were expansive and forests were limited, eucalypts (eucalyptus spp.) and pines (pinus spp.) were grown on grasslands for preventing land degradation through deforestation and for providing additional source of income for rural poor. This study shows that in addition to detrimental consequence of eucalyptus and pine forests on soil resources, conversion of Bukoban grasslands to forests has negatively impacted livelihood of the rural poor. Growing eucalypts and pines on grasslands prevented a farming system that enabled integration of grasslands, cattle keeping and crop production. Consequently, the grasslands role of nutrients cycling was disrupted, food crop production reduced, home-gardens productivity declined, majority deprived important livelihood asset and foreign income flow into the area reduced. [source] Understanding future ecosystem changes in Lake Victoria basin using participatory local scenariosAFRICAN JOURNAL OF ECOLOGY, Issue 2009Eric O. Odada Abstract Understanding future ecosystem changes is central to sustainable natural resource management especially when coupled with in-depth understanding of impacts of drivers, such as governance, demographic, economic and climate variations and land use policy. This offers comprehensive information for sustainable ecosystem services provision. A foresight process of systematic and presumptive assessment of future state and ecosystem integrity of Lake Victoria basin, as participatory scenario building technique, is presented. Four scenarios have been illustrated as possible future states of the basin over the next twenty years. Using a scenario building model developed in Ventana Simulation (VENSIM®) platform, the paper presents a scenario methodology for tracking changes in lake basin ecosystem status. Plausible trends in land use change, changes in lake levels and contribution of fisheries are presented. This is part of an initial attempt to setup long-term environmental policy planning strategies for Lake Victoria basin. The assumptions, driving forces, impacts and opportunities under each scenario depict major departure and convergence points for an integrated transboundary diagnosis and analysis of regional issues in the basin as well as strategic action planning for long-term interventions. The findings have been presented in terms of temporal, spatial, biophysical and human well-being dimensions. The attempts in this study can be embedded in a policy framework for basin management priority setting and may guide partnerships for environmental management. [source] Reframing applied disease stigma research: a multilevel analysis of diabetes stigma in GhanaJOURNAL OF COMMUNITY & APPLIED SOCIAL PSYCHOLOGY, Issue 6 2006Ama de-Graft Aikins Abstract Research suggests that rural and urban Ghanaians living with uncontrolled diabetes,typified by extreme weight loss,experience HIV/AIDS-related stigma. This paper reports a multilevel analysis of this stigma within the broader context of diabetes handicap in two rural communities. Two key findings emerge. First, the content of stigma constitutes social representations of HIV/AIDS, and to internalized and projected collective attributions of protracted illness to witchcraft or sorcery. Thus the stigma experienced by people with uncontrolled diabetes is not specific to the disease category ,diabetes' and distant others affected by it. Second, extreme biophysical disruption, which precipitates misperceptions, stigma and/or discrimination, is both cause and consequence of financial destitution and psychosocial neglect. Both forms of handicap have deeper pre-stigma roots in poverty and the socio-psychological and cultural impact of long-term illness. Thus the actuality or threat of diabetes stigma has to be understood in terms of diabetes handicap, which in turn has to be understood as a product of shared responses to long-term illness in communities constantly negotiating financial, health and psychological insecurities. The scope for multifaceted/multilevel intervention is considered taking into account the biophysical and psychological impact of illness and the socio-psychological and structural realities of diabetes care in Ghana. Copyright © 2006 John Wiley & Sons, Ltd. [source] A computationally inexpensive modification of the point dipole electrostatic polarization model for molecular simulationsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 3 2003George A. Kaminski Abstract We present an approximation, which allows reduction of computational resources needed to explicitly incorporate electrostatic polarization into molecular simulations utilizing empirical force fields. The proposed method is employed to compute three-body energies of molecular complexes with dipolar electrostatic probes, gas-phase dimerization energies, and pure liquid properties for five systems that are important in biophysical and organic simulations,water, methanol, methylamine, methanethiol, and acetamide. In all the cases, the three-body energies agreed with high level ab initio data within 0.07 kcal/mol, dimerization energies,within 0.43 kcal/mol (except for the special case of the CH3SH), and computed heats of vaporization and densities differed from the experimental results by less than 2%. Moreover, because the presented method allows a significant reduction in computational cost, we were able to carry out the liquid-state calculations with Monte Carlo technique. Comparison with the full-scale point dipole method showed that the computational time was reduced by 3.5 to more than 20 times, depending on the system in hand and on the desired level of the full-scale model accuracy, while the difference in energetic results between the full-scale and the presented approximate model was not great in the most cases. Comparison with the nonpolarizable OPLS-AA force field for all the substances involved and with the polarizable POL3 and q90 models for water and methanol, respectively, demonstrates that the presented technique allows reduction of computational cost with no sacrifice of accuracy. We hope that the proposed method will be of benefit to research employing molecular modeling technique in the biophysical and physical organic chemistry areas. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 267,276, 2003 [source] Trafficking and potential assembly patterns of ,-containing GABAA receptorsJOURNAL OF NEUROCHEMISTRY, Issue 3 2007Brian L. Jones Abstract Incorporation of the , subunit into the GABAA receptor has been suggested to confer unusual, but variable, biophysical and pharmacological characteristics to both recombinant and native receptors. Due to their structural similarity with the , subunits, , subunits have been assumed to substitute at the single position of the , subunit in assembled receptors. However, prior work suggests that functional variability in ,-containing receptors may reflect alternative sites of incorporation and of not just one, but possibly multiple , subunits in the pentameric receptor complex. Here we present data indicating that increased expression of ,, in conjunction with ,2 and ,3 subunits, results in expression of GABAA receptors with correspondingly altered rectification, deactivation and levels of spontaneous openings, but not increased total current density. We also provide data that the , subunit, like the ,3 subunit, can self-export and data from chimeric receptors suggesting that similarities between the assembly domains of the ,3 and the , subunits may allow the , subunit to replace the ,, as well as the ,, subunit. The substitution of an , for a ,, as well as the , subunit and formation of receptors with alternative patterns of assembly with respect to , incorporation may underlie the observed variability in both biophysical and pharmacological properties noted not only in recombinant, but also in native receptors. [source] Pharmaceutical and immunological evaluation of a single-shot hepatitis B vaccine formulated with PLGA microspheresJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2002Li Shi Abstract A single-shot Hepatitis B vaccine formulation using poly(d,l)-lactide-co-glycolide acid (PLGA) microspheres as a delivery system was examined using a variety of biophysical and biochemical techniques as well as immunological evaluation in C3H mice. PLGA microsphere encapsulation of the Hepatitis B surface antigen (HBsAg), a lipoprotein particle, resulted in good recoveries of protein mass, protein particle conformational integrity, and in vitro antigenicity. Some partial delipidation of the HBsAg, however, was observed. The loading and encapsulation efficiency of HBsAg into the PLGA microspheres were measured along with the morphology and size distribution of the vaccine-loaded PLGA microspheres. The in vitro release kinetics of HBsAg from the PLGA microspheres was evaluated and found to be affected by experimental conditions such as stirring rate. HBsAg showed enhanced storage stability at 37°C in the slightly acidic pH range reported to be found inside PLGA microspheres; thus, the antigen is relatively stable under conditions of temperature and pH that may mimic in vivo conditions. The immunogenicity of the microsphere formulations of HBsAg was compared with conventional aluminum adjuvant formulated HBsAg vaccine in C3H mice. Comparisons were made between aluminum formulations (one and two injections), PLGA microsphere formulations (single injection), and a mixture of aluminum and PLGA microsphere formulations (single injection). The nine-month serum antibody titers indicate that a single injection of a mixture of aluminum and PLGA-formulated HBsAg results in equal or better immune responses than two injections of aluminum-formulated HBsAg vaccine. Based on these invitro and in vivo studies, it is concluded that HBsAg can be successfully encapsulated and recovered from the PLGA microspheres and a mixture of aluminum-adjuvanted and PLGA-formulated HBsAg can auto-boost an immune response in manner comparable to multiple injections of an aluminum-formulated vaccine. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1019,1035, 2002 [source] Transboundary River Floods and Institutional Capacity,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2009Marloes H.N. Bakker Abstract:, While transboundary flood events have become more frequent on a global scale the past two decades, they appear to be overlooked in the international river basin (IRB) cooperation and management arena. The present study therefore combined geopolitical measures with biophysical and socioeconomic variables in an attempt to identify the IRBs with adequate institutional capacity for management of transboundary floods. It also classified basins that would possibly benefit from enlarging the institutional capacity related to transboundary floods. Of the 279 known IRBs, only 78 were represented by a transboundary rivers institution. A mere eight of the 153 identified institutions had transboundary flooding listed as an issue in their mandate. Overall, 43 basins, where transboundary floods were frequent during the period 1985-2005, had no institutional capacity for IRBs. The average death and displacement tolls were found to be lower in the 37 basins with institutional capacity, even though these basins experienced twice as much transboundary floods with significant higher magnitudes than those in basins without institutional capacity. Overall, the results suggested that institutional capacity plays a role in the reduction of flood-related casualties and affected individuals. River basins such as the Juba-Shibeli, Han, Kura-Araks, Ma, Maritsa, Po, Coco/Segovia, Grijalva, Artibonite, Changuinola, Coatan Achute, and Orinoco experienced more than one transboundary river flood, but have not yet set up any institutions for such events, or signed any appropriate treaties focused on floods. These basins were therefore recommended to consider focusing attention on this apparent lack of institutional capacity when it comes to managing transboundary flood events. [source] Household level tree planting and its implications for environmental management in the northwestern highlands of Ethiopia: a case study in the Chemoga watershed, Blue Nile basinLAND DEGRADATION AND DEVELOPMENT, Issue 4 2003W. Bewket Abstract The unsustainable exploitation and destruction of forests is a serious environmental concern in the developing countries of Africa. One of its main driving forces is the growing population causing a growing demand for fuelwood. In Ethiopia, as in many developing countries, there is a heavy dependence on and a growing demand for fuelwood. This dependence has been contributing to a widescale deforestation, as stated in various reports. Contrary to these reports, a study in the Chemoga watershed found a slightly increased forest cover during the past four decades, which was ascribed to households' tree planting practices. The objective of this study was to examine household level tree planting activities in reference to biofuel consumption patterns in four sample villages in the watershed. The results indicate that fuelwood and cattle dung accounted for nearly 100 per cent of the domestic energy consumption, with cattle dung contributing 34 per cent of the total. Fuelwood and dung combined, per capita biofuel consumption was estimated at 511,kg,yr,1, but with variations between the villages and socio-economic groups. Supply appears to have influenced the quantity of biofuels used. The scarcity of wood for fuel and other uses has forced households to plant trees. This has contributed to the increased forest cover of the watershed at the present as compared to that four decades ago. Number of trees planted showed variation between the villages and socio-economic groups, which is attributable to physical and human factors. In promoting tree planting, agroforesters and environmental management planners should therefore take into account local level biophysical and socio-economic realities. This agroforestry practice is a good short-term solution to the problem of fuelwood shortage, and also has many positive implications for environmental management and agricultural production. Thus, it has to be encouraged. Spatially aggregated, local level agroforestry practices contribute positively towards global ecosystem health. Copyright © 2003 John Wiley & Sons, Ltd. [source] A multi-angular mass spectrometric view at cyclic nucleotide dependent protein kinases: In vivo characterization and structure/function relationshipsMASS SPECTROMETRY REVIEWS, Issue 4 2008Arjen Scholten Abstract Mass spectrometry has evolved in recent years to a well-accepted and increasingly important complementary technique in molecular and structural biology. Here we review the many contributions mass spectrometry based studies have made in recent years in our understanding of the important cyclic nucleotide activated protein kinase A (PKA) and protein kinase G (PKG). We both describe the characterization of kinase isozymes, substrate phosphorylation, binding partners and post-translational modifications by proteomics based methodologies as well as their structural and functional properties as revealed by native mass spectrometry, H/D exchange MS and ion mobility. Combining all these mass spectrometry based data with other biophysical and biochemical data has been of great help to unravel the intricate regulation of kinase function in the cell in all its magnificent complexity. © 2008 Wiley Periodicals, Inc. Mass Spec Rev 27: 331,353, 2008 [source] Microvascular Rheology and HemodynamicsMICROCIRCULATION, Issue 1 2005HERBERT H. LIPOWSKY ABSTRACT The goal of elucidating the biophysical and physiological basis of pressure,flow relations in the microcirculation has been a recurring theme since the first observations of capillary blood flow in living tissues. At the birth of the Microcirculatory Society, seminal observations on the heterogeneous distribution of blood cells in the microvasculature and the rheological properties of blood in small bore tubes raised many questions on the viscous properties of blood flow in the microcirculation that captured the attention of the Society's membership. It is now recognized that blood viscosity in small bore tubes may fall dramatically as shear rates are increased, and increase dramatically with elevations in hematocrit. These relationships are strongly affected by blood cell deformability and concentration, red cell aggregation, and white cell interactions with the red cells and endothelium. Increasing strength of red cell aggregation may result in sequestration of clumps of red cells with either reductions or increases in microvascular hematocrit dependent upon network topography. During red cell aggregation, resistance to flow may thus decrease with hematocrit reduction or increase due to redistribution of red cells. Blood cell adhesion to the microvessel wall may initiate flow reductions, as, for example, in the case of red cell adhesion to the endothelium in sickle cell disease, or leukocyte adhesion in inflammation. The endothelial glycocalyx has been shown to result from a balance of the biosynthesis of new glycans, and the enzymatic or shear-dependent alterations in its composition. Flow-dependent reductions in the endothelial surface layer may thus affect the resistance to flow and/or the adhesion of red cells and/or leukocytes to the endothelium. Thus, future studies aimed at the molecular rheology of the endothelial surface layer may provide new insights into determinants of the resistance to flow. [source] A restoration genetics guide for coral reef conservationMOLECULAR ECOLOGY, Issue 12 2008ILIANA B. BAUMS Abstract Worldwide degradation of coral reef communities has prompted a surge in restoration efforts. They proceed largely without considering genetic factors because traditionally, coral populations have been regarded as open over large areas with little potential for local adaptation. Since, biophysical and molecular studies indicated that most populations are closed over shorter time and smaller spatial scales. Thus, it is justified to re-examine the potential for site adaptation in corals. There is ample evidence for differentiated populations, inbreeding, asexual reproduction and the occurrence of ecotypes, factors that may facilitate local adaptation. Discovery of widespread local adaptation would influence coral restoration projects mainly with regard to the physical and evolutionary distance from the source wild and/or captive bred propagules may be moved without causing a loss of fitness in the restored population. Proposed causes for loss of fitness as a result of (plant) restoration efforts include founder effects, genetic swamping, inbreeding and/or outbreeding depression. Direct evidence for any of these processes is scarce in reef corals due to a lack of model species that allow for testing over multiple generations and the separation of the relative contributions of algal symbionts and their coral hosts to the overall performance of the coral colony. This gap in our knowledge may be closed by employing novel population genetic and genomics approaches. The use of molecular tools may aid managers in the selection of appropriate propagule sources, guide spatial arrangement of transplants, and help in assessing the success of coral restoration projects by tracking the performance of transplants, thereby generating important data for future coral reef conservation and restoration projects. [source] Rafts and sphingolipid biosynthesis in the kinetoplastid parasitic protozoaMOLECULAR MICROBIOLOGY, Issue 3 2004Paul W. Denny Summary Although the concept of eukaryotic lipid rafts arouses controversy, recent biophysical studies strongly indicate that inducible, stable and relatively large rafts are a feature of activated mammalian cells. These studies allow us to consider the functional role of lipid rafts in kinetoplastid parasites, which are particularly rich in lipid-anchored surface molecules. Morphological, biochemical and genetic studies indicate that lipid rafts (and sphingolipid biosythesis) are important in the differentiation of extracellular Leishmania to mammalian-infective metacyclic promastigotes, perhaps orchestrating the clearly observable reorganization of the plasma membrane during this process that leads to an activated metacyclic primed for invasion. However, the first step in the sphingolipid biosynthetic pathway (mediated by serine palmitoyltransferase), and at least regulated, de novo sphingoid base and ceramide synthesis, are not essential for the pathogenesis of intramacrophage Leishmania amastigotes. [source] | |||||||||||||||||||||||||||||||||||||